Determinants of basal insulin secretion in man are less well characterized than those of stimulated insulin secretion. The present studies are designed to systematically evaluate control of basal insulin secretion during short-term starvation. Previous work done in our laboratory has shown that plasma glucose is not a major determinant of insulin secretion during starvation. However, prostaglandins, serotoninergic and gastrointestinal factors appears to influence insulin secretion. The proposed work will attempt to further study the roles of each of these factors in basal insulin secretion during short-term starvation in healthy volunteer subjects.